The subject matter disclosed herein relates generally to correcting wiring errors in electrical power system wiring, and, more particularly, to methods and apparatus for redefining electrical power system wiring configurations within an industrial automation application.
In a typical industrial automation electrical power distribution system, electrical power is provided to various loads. Such loads may include, for example, various motors and drives used by the end consumer to control an industrial automation application. Because energy management and understanding energy costs are a major focus in the manufacturing industry, devices commonly referred to as power meters or power monitors are commonly installed in the electrical power system. The power monitor is used for cost effective energy monitoring of industrial automation applications where load profiling, cost allocation, or other energy related control or monitoring may be beneficial.
Likely the most common problem that occurs when a power monitor is installed (electrically wired) within an electrical power system is that the input wiring connecting the electrical power system to the power monitor is incorrect, for a variety of reasons. For example, it is fairly common for the wiring of one or more current transformers or potential transformers (when present) to be 180 degrees out of phase, for the phase sequence to be incorrect, or for incorrect correlation of the voltage and current phases. These and other wiring errors result in incorrect metering data and can sometimes be difficult to identify. In addition, the wiring error may not be discovered at the time of installation. In many situations, the wiring corrections can not be made until the power can be shut down for safety and/or continuous process reasons. This may mean the wiring error can not be corrected for several weeks or months.
Prior devices have attempted to address this problem. There are some power monitoring devices that are able to provide a phasor diagram as a way to help the user identify possible wiring problems. Nevertheless, interpreting a phasor diagram requires someone with sufficient knowledge of phasor vectors and how to translate the phasor diagram to a possible wiring error. There are also some power monitoring devices that need to be told of the problem, such as that the wiring (current inputs) from a current transformer are inverted. After the user tells the monitoring device of the problem, the inverted current transformer wiring can be corrected by firmware in the monitoring device without needing to rearrange (rewire) the current inputs. Nevertheless, these prior devices require user analysis and user input in order to detect a wiring error and/or to correct the wiring error so that the power monitor can provide accurate metering data.
It would, therefore, be desirable to have methods and apparatus to automatically detect wiring error(s), identify to the user what wiring error has been detected, and redefine the wiring configuration, so that the power monitor can provide accurate metering data. The methods and apparatus desirably provide an indication to the user that the power monitor has redefined the electrical power system wiring.